Grease manufacturers have attempted to prepare alkali and alkaline earth metal greases from enhanced vegetable oils with limited success. The high temperatures required degrade the vegetable oil thickener substitute and vegetable oil diluent. Further, high temperatures cause the antioxidants and viscosity modifiers to separate out.
U.S. Pat. No. 2,697,693 (Browning et al., Dec. 21, 1954) relates to improvements in the manufacture of lithium soap greases. More particularly, it relates to improvements in the manufacture of greases comprising lithium 12-hydroxy stearate or the lithium soap of hydrogenated castor oil and a lubricant base such as a mineral lubricating oil or the like.
U.S. Pat. No. 2,824,066 (Musselman et al., Feb. 18, 1958) relates to a multi-purpose soda base lubricating grease. The preparation of the grease preferably involves the in situ formation of a fatty acid soap in a mineral oil. A typical preparation comprises weighing the solvent-extracted oil and a calculated amount of sodium hydroxide into a mixing vessel and then heating these materials to an elevated temperature, generally in excess of 150.degree. F., and a calculated amount of fatty acid is then weighted into the mixer. The mixer is again started and heating is continued at a temperature of approximately 300.degree. F. After heating at the elevated temperature for about 10 to 15 minutes, until saponification is complete, an additional quantity of solvent-extracted oil is added to the mixer and heating is continued until a total processing time of about 21/2 to 3 hours has elapsed. Heating is then discontinued and during the cooling of the crude grease mixture, an additional calculated quantity of solvent-extracted oil is added with the final oil addition being made at a temperature in the neighborhood of 225.degree. to 230.degree. F. Cooling is then continued until the grease is at a temperature suitable for packaging.
U.S. Pat. No. 4,303,538 (Pratt et al., Dec. 1, 1981) relates to oxyaluminum acylates containing more than about 75 mole percent of an aromatic carboxylic acid, but less than about 95 mole percent of aromatic acid which can be prepared, and, further, that such oxyaluminum acylates can be used to make aluminum complex grease of seemingly excellent quality. The greases made from such oxyaluminum acylates are produced without the use of water and without the production of water or alcohol as by-products.
U.S. Pat. No. 4,392,967 (Alexander, Jul. 12, 1983) is directed to a process for continuously manufacturing a lubricating grease using a screw process unit. More particularly, the process of this reference comprises:
(a) introducing feed materials and lubricating oil into selected locations of a screw process unit which contains a series of adjacent, longitudinally connected barrel sections for performing different operative steps and houses a rotating screw device traversing the interior to the barrel sections and having separate elements along its length to perform desired operations; PA1 (b) mixing and conveying said feed materials along said process unit through the adjacent barrel sections by continuous operation of said rotating screw; PA1 (c) controlling the temperature of said material while it is being conveyed through said process unit by use of various heat exchange means which are located in or adjacent to each barrel to aid in carrying out the operative steps of dispersion, reaction, dehydration and/or homogenization; PA1 (d) venting water resulting from the dehydration of the feed mixture at selected barrel discharge points in said process unit; PA1 (e) introduction of additional oil and/or additives at downstream barrel sections following the dehydration step; PA1 (f) homogenization of said complete grease formulation by continued rotation of said screw device; and PA1 (g) removal of the finished lubricating grease from the end barrel section of said screw process unit. PA1 (A) a base oil wherein the base oil is a natural oil or synthetic triglyceride of the formula ##STR2## wherein R.sup.1, R.sup.2 and R.sup.3 are aliphatic groups that contain from about 7 to about 23 carbon atoms; PA1 (B) at least one performance additive comprising PA1 (C) a thickener wherein the thickener (C) is a reaction product of (C1) a metal based material and (C2) a carboxylic acid or its ester, wherein the metal based material (C1) comprises a metal oxide, metal hydroxide, metal carbonate or metal bicarbonate, wherein the metal is an alkali or alkaline earth metal and wherein the carboxylic acid (C2) is of the formula R.sup.18 (COOR.sup.19).sub.n wherein R.sup.18 is an aliphatic group that contains from 4 to 29 carbon atoms, R.sup.19 is hydrogen or an aliphatic group that contain from 1 to 4 carbon atoms and n is an integer of from 1 to 4. PA1 (a) making a solution of (A) and (B) or (A), (B), (D) and/or (E) with (C1) and (C2), thereby providing a mixture; PA1 (b) heating said mixture to a temperature of from 82.degree. to about 105.degree. C. to form (C); PA1 (c) heating the mixture to a final temperature of about 145.degree. C. for an alkaline metal or to about 200.degree. C. for an alkali metal; and PA1 (d) cooling the mixture to form a grease. PA1 (a) making a solution of (A) and (B) or (A), (B), (D) and/or (E) with (C1) and (C2), thereby providing a first mixture; PA1 (b) heating said first mixture to a temperature of from 82.degree. to about 105.degree. C. to form (C) thereby providing a first heated mixture; PA1 (c) heating the first heated mixture to a final temperature of about 145.degree. C. for an alkaline metal or to about 200.degree. C. for an alkali metal; PA1 (d) adding at 110.degree.-145.degree. C. for an alkaline earth metal or 170.degree.-200.degree. C. for an alkali metal, subsequent portions of (A) or the solution of (A) and (B) or (A), (B), (D) and/or (E) to provide a second mixture; and PA1 (e) permitting this mixture to cool to form a grease. PA1 (1) an alkyl phenol, PA1 (2) a benzotriazole, and PA1 (3) an aromatic amine.
U.S. Pat. No. 5,116,522 (Brown et al., May 26, 1992) concerns a lubricating composition having improved low temperature and high temperature properties. More specifically, a lubricating composition comprising (1) a lubricating oil, (2) a thickener, (3) a VI improver, and (4) a copolymer of ethylene with at least one compound selected from the group of vinyl acetate, alkyl acrylate, or alkyl methacrylate, has been found to have both excellent high temperature adhesiveness and low temperature slumpability. The ethylene copolymer used in this invention must have a Melt Index of at least about 40 g/10 min. and should contain from about 10 to about 40 wt. % vinyl acetate, alkyl acrylate, or alkyl methacrylate. Preferably, the Melt Index should be between about 40 and about 10,000, more preferably between about 40 and about 5,000, and most preferably between about 40 and about 2,500 g/10 mins.
U.S. Pat. No. 5,154,840 (Drake et al., Oct. 13, 1992) provides an environmentally friendly grease composition. The base components of this lubricating composition include a white mineral oil in the amount of about 65 to about 85% by weight based on total weight of the composition, an extreme pressure additive comprising a solid friction modifier in an amount of about 1 to about 20 wt. %, a thickener and a minor amount of one or more oil dispersible additives in amounts sufficient to enhance the performance characteristics of the greases. Each of the extreme pressure additive, thickener, and the one or more oil dispersible additives is essentially free of heavy metals, particularly arsenic, antimony, barium, cadmium, chromium, copper, iron, lead, mercury, molybdenum, nickel, selenium, vanadium and zinc.
U.S. Pat. No. 5,256,321 (Todd, Oct. 26, 1993) relates to improved grease compositions substantially free of boron and boron-containing compounds, comprising a major amount of an oil-based simple metal soap thickened base grease and a minor amount of at least one phosphorus and sulfur containing composition sufficient to increase the dropping point of the base grease, as determined by ASTM procedure D-2265, by at least 30.degree. C.